I am new to this site. I have colored my hair twice in the past 3-4 months with henna. I wanted to go to a more natural hair color product. I have naturally curly hair. But since the henna my hair has seemed to have lost some of it's curl. And it is very dry. I have quite a bit of gray at the front and temple areas. So, I was going to try a semi-permanent hair color NOT henna. I was only going to apply the semi-perm to the gray areas not my whole head. Does anyone know how long after using henna it is ok to try a chemical semi perm? The grays are all gray again, not red from the henna. I just don't want to turn my hair some crazy color ... Also, will the curl returned?

The lawson in the henna is permanently bonded to the proteins in hair you likely have to grow that out, yes it's well known to loosen curl. Henna'd hair needs regular deep treatments afterwards, have you done this? The dryness should not remain, did you use pure body art quality henna or hair dye 'henna' with other ingredients?

When you say a 'chemical' semi permanent do you mean the stuff that is in a conditioner base that would not damage your hair even if you left it twenty four hours or a demi permanent containing alkaline ingredients that will lift the cuticle? Two different animals that are often confused.

I would not ever advocate mixing any chemical demi or permanent with henna, the results are too unpredictable and it's impossible not to get overlap even if you could find a way of perfectly matching the colour. It's not simply a 'crazy colour' result you should be worrying about, some ingredients in box dyes react badly with ingredients in lower quality henna colourants and can destroy your hair. However I think you will struggle to get a semi permanent to take to virgin grey hair.